This invention relates to improvements in the stencil screen printing art and more particularly to squeegee mechanisms for applying ink evenly over patterned printing screens.
In manual stencil screen printing in contrast to the high-speed printing, a pattern is designed on a fine fabric screen. The pattern defines which areas ink can or cannot pass through. The screen is securely mounted on a frame of generally rectangular configuration. The fabric to be printed in held tautly beneath the frame and the screen is positioned over the fabric in close contact therewith. The ink is pressed through the screen in accordance with the pattern by a hand-held squeegee which is a relatively rigid, rubber, blade-like element by which the ink is swept across the surface of the screen.
The squeegee is either a separate element which is hand held or which is mechanically connected to the framework by suitable linkages and guide rods permitting movement in predetermined paths over the screen. This invention is directed toward improvements in the latter type of squeegee.
The prior art mechanical squeegees include supporting guide rods which are attached to the framework by suitable mounting means and to which the squeegee is attached. The squeegee generally is permitted to move freely in one direction which is the direction in which the squeegee is facing and which will be termed the "longitudinal" direction herein. However, it is not permitted free movement laterally; that is, in the direction of its longitudinal axis. Usually, the squeegee is locked in a fixed position along the length of its lateral support. Hence when the squeegee is moved in the longitudinal direction, it is limited to a path whose width is substantially equal to the length of the squeegee blade. One of the main advantages of the mechanical arrangements is that the guide rods insure that the squeegee applies a uniform, downward force on the printing screen for a selected path. One of its disadvantages, however, is its limited movement in only a single path as mentioned above, longitudinally, when in operation. It can not effectively "sweep" the ink from the perimeter of the screen to the center since it is prohibited from rotational movement and free lateral movement. Frequently a second, hand-held squeegee, card, scraper, or the like is used in conjunction with a mechanical squeegee to sweep ink from the outer edges of the screen toward the center. This is a messy procedure and ink is quite likely to get on the user's hands and clothes.
It is an object of this invention to provide a mechanical squeegee apparatus which combines the advantages of both the mechanical squeegee and the hand-held squeegee. While the mechanical squeegees of the prior art are faster and much neater than the hand-held squeegee, they can not duplicate the movements of the hand-held squeegee in sweeping the ink from the outer confines of the screen toward the center and into the design area.
It is another objective of this invention to provide a squeegee which can move freely longitudinally and laterally and can be rotated or twisted about a vertical axis to an angular orientation relative to its paths of travel over the screen.
It is a further objective of this invention to provide a squeegee apparatus which can be mounted as a unit on existing printing screen frames.
It is another objective of this invention to provide a squeegee apparatus having a handle attached to the squeegee blade in such a manner that by the operator using one hand only the squeegee can be passed through all of the various movements.